When, in the course of a proceeding under this chapter, it appears to the court that the welfare of a minor will be promoted by the appointment of a guardian or custodian of the minor's person, the court may make the appointment. The court shall have a summons issued and served upon the parents of the minor, if they can be found, in a manner and within a time before the hearing that the court considers reasonable. The court may determine whether the father, mother, another suitable person, or the department shall have the custody and control of the minor. If the minor is of sufficient age and intelligence to state desires, the court shall consider them.